Globe Nutsedge (Yellow Nutsedge)
This is a perennial weed that produces zillions of seeds by a very thin creeping stem. The roots are tipped by small tubers.
Very invasive. To eliminate the weed, digging down to get the tubers could be helpful (see photo). Cutting them down as soon as they appear will also help. They can cause havoc in the lawn.
The bloom of the weed is interesting for cutting and arranging in a weed bouquet.